It is a well-known fact that, by introducing a piece or strip of viscoelastic elastomer material onto the frame or strings of a racket, one can influence vibratory phenomena. However, such antivibration devices used to date have exhibited one or more of the following defects:
(1) ineffectiveness due to their positioning on the frame or in the racket strings PA0 (2) difficulties involved in their installation and fastening which result in their lack of cohesion to the strung hitting surface during ball impact PA0 (3) complexity of utilization PA0 (4) interference of the over-sized device with desired trajectory of the ball
The device disclosed in French Patent No. 2,585,256 of July 29, 1985, in addition to its uncertain lateral deportment during repeated impact, offers no permanent cohesion during vibratory modes on the strung hitting surface, due to the rigidity of its basic material as well as to the limited number of strings with which it is in direct contact. Its excessive width necessarily compensates for the minimal thickness required in order to fix it onto the strung hitting surface, but this means that the device is too wide to be interlaced into the meshed surface of the racket, particularly close to the area of impact where maximum string reverberation occurs. The rigidity of this device also tends to modify the central ball-impact zone and, being nonretractable, it contributes to deflecting the ball in the event of direct contact.
The device disclosed in French Patent No. 2,585,257 based on French Patent No. 1,398,833 of Mar. 31, 1964, is probably too bulky to be really effective, since it is fixed to only one square of the meshed racket surface. Moreover, its sprue is stretched out by compression on the periphery of the racket surface, which renders the device ineffective in vibratory modes.